1. Field of the Invention
The present invention relates to a light-emitting element, and in particular to a semiconductor light-emitting element such as a light-emitting diode (LED).
2. Description of the Related Art
Conventionally, in a semiconductor light-emitting element such as a light-emitting diode (LED), a pad electrode or another connection electrode is provided on the semiconductor layer (or a contact layer) on the surface of the element. Supply current from the exterior is injected into the semiconductor light-emitting element through the connection electrode and the light-emitting element is caused to emit light. There is used a configuration in which a wiring electrode connected to the connection electrode is provided on the contact layer, and a current is injected into the semiconductor light-emitting element.
In an LED in which the surface of the semiconductor light-emitting element is the light-extraction surface, it is important chat a current flows uniformly in the plane of the semiconductor layer. In particular, in recent years, there have been efforts to increase the area of LEDs due to demands such as those for increased brightness or light emission efficiency of LEDs. Also, so-called thin-film LCDs nave been fabricated. These thin-film LEDs are formed by growing a semiconductor layer comprising, e.g., a GaN-based compound semiconductor on a sapphire or another growth substrate and subsequently separating the growth layer from the substrate. In an LED of such description, it is important in terms of obtaining a high-performance element to prevent current crowding or concentration in the plane of the semiconductor layer and obtain a uniform current distribution.
For example, Japanese Unexamined Patent Application Publication No. 2008-543068 (“Patent Reference 1” hereafter) discloses an LED in which the width of the wiring electrode becomes smaller (the wiring electrode becomes thinner) as the distance from a bonding pad increases. Also, Japanese Unexamined Patent Application Publication No. H05-145119 (“Patent Reference 2” hereafter) discloses an LED having a wiring electrode comprising a plurality of orders of branches extending as lines from a pad section.